NSD creation fails with a message referring to an existing NSD
The following message:
6027-1662 Disk descriptor descriptor refers to an existing NSD name.
may appear when trying to create a Network Shared Disk on a disk that had previously been used as an
NSD by GPFS. This situation arises if the mmdelnsd command failed to complete. These instructions
describe how to delete an NSD that is not being used by GPFS anymore.
NSDs are deleted with the mmdelnsd command. Internally, this is a two-step process:
1. Remove the NSD definitions from the GPFS control information.
2. Zero-out GPFS-specific data structures on the disk.
If for some reason the second step fails, for example because the disk is damaged and cannot be written
to, the mmdelnsd command issues a message describing the error and then another message stating the
exact command to issue to complete the deletion of the NSD. If these instructions are not successfully
completed, a subsequent mmcrnsd command can fail with
6027-1662 Disk descriptor descriptor refers to an existing NSD name.
This error message indicates that the disk is either an existing NSD, or that the disk was previously an
NSD that had been removed from the GPFS cluster using the mmdelnsd -p command, and had not been
marked as available.
If the GPFS data structures are not removed from the disk, it might be unusable for other purposes. For
example, if you are trying to create an AIX volume group on the disk, the mkvg command might fail with
messages similar to:
0516-1339 /usr/sbin/mkvg: Physical volume contains some 3rd party volume group.
0516-1397 /usr/sbin/mkvg: The physical volume hdisk5, will not be added to the volume group.
0516-862 /usr/sbin/mkvg: Unable to create volume group.
The easiest way to recover such a disk is to temporarily define it as an NSD again, using the -v no option,
and then delete the just-created NSD. For example:
mmcrnsd -F filename -v no
Options
- -v {yes |no}
- Verify the disk is not already formatted as an NSD.
A value of -v yes specifies that the NSD are to be created only if the disk has not been formatted by a previous invocation of the mmcrnsd command, as indicated by the NSD volume ID on sector 2 of the disk. A value of -v no specifies that the disk is to be formatted irrespective of its previous state. The default is -v yes.